Many buildings are equipped with doors that require transfer of electric power from the door frame to locks, latches, panic devices, alarms, cameras, I.D. readers and the like mounted on or in the door. The prior art provides examples of transfer of electrical power through knuckle hinges (hereinafter referred to as butt hinges) such as those described in U.S. Pat. Nos. 3,838,234; 3,84286; and 4,412,711. U.S. Pat. No. 7,063,042 provides an example of electrical transfer through a continuous gear butt hinge, not a surface mounted hinge.
A butt hinge is largely hidden from view when a door employing the hinge is closed. In contrast a surface mounted hinge is almost fully visible. An example of electrical transfer through a surface mounted continuous gear hinge can be found at the Pemko website. The Pemko product passes electricity through a flat cable that passes through a cutout in a portion of the gears.